Possible causes of oil residual on upper extension manifold?
Hi RX8Club, I got my 8 about a month ago. It is a stock 09 GT with 46k miles. This is my second 8 so I decided to take care of the common problems one at the time. The first thing I did was coil, plug, wires. Unfortunately, I found some oil inside the intake tube and the box, there was a quarter-sized oil mark on the intake filter. I changed the filter, cleaned the box and tube. After I put everything back, I found there are lots of oil residuals outside of the upper extension manifold (not sure if this is the right name?) and the area around oil cap. Does this mean there is an oil leak somewhere or it is the aftermath of an excessive amount of oil inside the throttle body? :dunno:
https://cimg3.ibsrv.net/gimg/www.rx8...3cd3501ebc.jpg https://cimg5.ibsrv.net/gimg/www.rx8...ffdd14f007.jpg Oil build-up on the lower part of the upper manifold There is no sign of power loss and rough idle, I do have some hissing noise from 3k-4k around the place where upper extension manifold is. Any idea of what might be the cause? Thanks |
Oil on the upper intake manifold usually means that somebody spilled oil during an oil change.
Oil in the airbox and accordion tube is probably from overfilling. |
Originally Posted by NotAPreppie
(Post 4824012)
Oil on the upper intake manifold usually means that somebody spilled oil during an oil change.
Oil in the airbox and accordion tube is probably from overfilling. |
Oil as pictured definitely looks like spillage from oil filling. For a car that requires frequent oil adding they could not have put the filler any further back in the engine bay. Even with a funnel it is a stretch. There is a slight possibility it is a bad seal on the filler cap.
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Originally Posted by speedieone
(Post 4824136)
Oil as pictured definitely looks like spillage from oil filling. For a car that requires frequent oil adding they could not have put the filler any further back in the engine bay. Even with a funnel it is a stretch. There is a slight possibility it is a bad seal on the filler cap.
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I've been wondering the same thing. I have that oil residue in those 2 same exact places. and i get like a light metallic scraping/hissing sound from 5k to 6k which again can not find a solution for. My theory is that there is a leak somewhere that I can't visibly dripping very slowly on to the exhaust manifold and cooking off that oil and it then settles on the plastic, but that isn't plausible since the residue is only apparent in those 2 places
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Originally Posted by Jdmx13b
(Post 4824219)
I've been wondering the same thing. I have that oil residue in those 2 same exact places. and i get like a light metallic scraping/hissing sound from 5k to 6k which again can not find a solution for. My theory is that there is a leak somewhere that I can't visibly dripping very slowly on to the exhaust manifold and cooking off that oil and it then settles on the plastic, but that isn't plausible since the residue is only apparent in those 2 places
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Originally Posted by Jdmx13b
(Post 4824219)
I've been wondering the same thing. I have that oil residue in those 2 same exact places. and i get like a light metallic scraping/hissing sound from 5k to 6k which again can not find a solution for. My theory is that there is a leak somewhere that I can't visibly dripping very slowly on to the exhaust manifold and cooking off that oil and it then settles on the plastic, but that isn't plausible since the residue is only apparent in those 2 places
The fact that it goes away after 6k RPM could just be the fact that the engine noise drowns it out. An audible vacuum leak should be obvious when looking at fuel trims. If you don't have an Bluetooth OBD-II adapter and smartphone app, get one and log MAF rate, AFR/Lambda and long term fuel trims as to wind it out to redline. Or, you could just be hearing things.
Originally Posted by phaeton217
(Post 4824283)
I thought the hissing is caused by the excessive amount of oil inside the manifold. But I have not experienced any CELs and the car drives fine so I assume it is caused by overfill. The hissing sound on my car is like the sound of wind noise, it is gone (or covered by engine noise) after 4k.
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Originally Posted by NotAPreppie
(Post 4824305)
I can't think of a way that oil in the UIM or LIM would cause any noise audible from inside the cabin. For the most part, it will just sit there in the intake, (very) slowly being pulled into the engine. Some may leak forward onto the filter. |
Originally Posted by phaeton217
(Post 4824312)
Is the induction noise from the intake particularly loud during 3k-4k rpm?
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Originally Posted by NotAPreppie
(Post 4824315)
Not unless you have an aftermarket intake or the VFAD is stuck open.
https://www.youtube.com/watch?v=t28K...ature=youtu.be |
I figured the sound is not obvious in open area so I did a recording in the garage. I might be paranoid about sound but the sound of the engine change to a hissing noise after 3000 rpm. One thing I need to mention is I just installed MeganRacing motor mounts, I do not know if solid engine mounts would give more noisy engine or not. Any inputs would be greatly appreciated! |
I don't know if the VFAD will open if the engine isn't under. I'm pretty certain I read somewhere that the SSV, VDI and APV won't open simply by rev'ing it while stationary.
I don't have the best ear for induction noises so I'll let others chime in. |
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